Japan's Salmon Catch Drops by Over 10% Year-on-Year Due to Warming and Climate Anomalies

Sakata, Yamagata Prefecture, Fish Catch Down 17% Year-on-Year
"Rising Water Temperatures Prevent Salmon Return... Concerns Over Prolonged Impact"

The rapid rise in sea temperatures due to global warming has caused a significant decrease in salmon catches in Japan, resulting in substantial damage to the fisheries industry. Beyond concerns over food supply, difficulties in securing salmon eggs for breeding fry have emerged, raising fears of a collapse in the aquaculture industry.

Salmon from Sakata City, Yamagata Prefecture, Japan. (Photo by NHK)

According to NHK on the 22nd, in Sakata City, Yamagata Prefecture?Japan's second-largest salmon fishing area after Hokkaido?the number of salmon caught as of the end of last month was 1,329, which is only 17% compared to 7,635 in the same period last year and 28% compared to 4,762 recorded two years ago. Normally, salmon fishing starts in mid-September, but this year, salmon did not return on time, delaying the start by about two weeks and causing a sharp decline in catches.

Not only in Yamagata Prefecture but also on the Japanese mainland (Honshu), salmon catches have drastically decreased this year. The number of salmon caught in rivers by the end of September was only about 9% compared to the same period last year. Even in Miyagi and Iwate Prefectures, which are closer to the Pacific Ocean and fared somewhat better, catches remained at only 10-20% of last year's levels.

Experts attribute the main cause of this decline in salmon catches to the rise in sea temperatures. Masahide Kaeriyama, Professor Emeritus at Hokkaido University, analyzed the average sea surface temperature off the coast of Yamagata Prefecture in September this year based on data from the Japan Meteorological Agency and found it to be the highest in the past 100 years. In October, sea surface temperatures were also 1 to 2 degrees Celsius higher than usual. Japan experienced record-breaking heat this summer, and in November, Tokyo saw abnormal weather with temperatures exceeding 25 degrees Celsius. These factors are believed to have contributed to the rapid rise in sea temperatures.

Professor Kaeriyama explained that if sea surface temperatures rise sharply, salmon that have gone far out to sea may mature while waiting for the right time to return, preventing them from coming back. Since sea temperatures were also high three years ago when salmon fry were released, relatively underdeveloped salmon are having difficulty returning. Typically, salmon fry stay in coastal areas to grow before heading out to sea, but with rising temperatures, the period salmon spend growing and residing in coastal waters shortens, causing them to leave before fully maturing and thus hindering proper growth.

Salmon roe rice bowl, a specialty of Yamagata Prefecture. Currently, frozen salmon roe is being used due to supply difficulties. (Photo by NHK)

With the sharp decline in salmon catches, the popular autumn dish of salmon roe rice bowls in Japan is becoming increasingly rare. Normally, fresh seasonal salmon roe would be available at this time, but due to the decrease in catches, frozen salmon roe from last year is being used, making it scarce. Even this supply is limited, causing deep concern among local fishermen.

There is even a significant shortage of salmon eggs needed to raise fry. Yamagata Prefecture supplies salmon eggs across Japan, but as salmon catches decrease, hatching fry is becoming difficult. There are concerns that the salmon aquaculture industry, which has a history of over 100 years, could be threatened.

Professor Kaeriyama stated, "If sea surface temperatures remain high, it creates an environment that is difficult for salmon to survive. If this condition continues next year, it could also affect salmon fry, which is a worrying situation."

This content was produced with the assistance of AI translation services.